Stress is a significant factor that can precipitate, exacerbate, and maintain psychopathology. Various neurotransmitter systems and intracellular transduction pathways have been implicated in mediating the stress response and linking it to psychopathology. The corticotropin-releasing factor (CRF) system is among the most important systems that have been identified. Over-activity of the CRF system is implicated in depression, anxiety, and other stress-related disorders such as irritable bowel syndrome and treatments aimed at reducing the activity of CRF may be very effective (Reul and Holsboer, 2002). Abundant preclinical evidence exists supporting the likelihood that treatments targeting this system offer a promising approach for treating certain neuropsychiatric, as well as, other stress-related physical illnesses. The proposed studies will further develop Promoter Neuroscience's (PNS) proprietary technologies and help accelerate the development of compounds capable of altering expression of the CRF system. PNS has developed catalytic lucleic acids as potential treatments for stress-related disorders. The novel approach taken by PNS to treat stress-related disorders involves the use of a DNA enzyme that targets the mRNA for CRF receptors or other elements of the CRF system. This DNA enzyme destroys the CRF receptor mRNA and subsequently reduces the amount of CRF receptor protein that is translated. PNS has demonstrated the feasibility of using catalytic nucleic acids to reduce CRF system protein levels and subsequently result in anxiolytic effects in animals. In this proposal we plan to perform a series of experiments that will allow for an improvement of our technology and will provide the foundation for future human clinical trials. First, we will fully explore the biochemical and behavioral effects of these enzymes using intracerebroventricular (ICV) administration. The optimal dose, frequency and duration of ICV DNA enzyme administration will be determined. Next, we will develop an HPLC based method to quantify levels of DNA enzymes in biological samples such as plasma, CSF, and brain tissue. We will characterize the in vivo pharmacokinetics of the DNA enzyme and finally we will determine the effects of peripherally administered DNA enzymes on the function of central and peripheral CRF systems.